JP2005173486A - Image forming apparatus - Google Patents
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- JP2005173486A JP2005173486A JP2003416769A JP2003416769A JP2005173486A JP 2005173486 A JP2005173486 A JP 2005173486A JP 2003416769 A JP2003416769 A JP 2003416769A JP 2003416769 A JP2003416769 A JP 2003416769A JP 2005173486 A JP2005173486 A JP 2005173486A
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本発明は、画像形成装置に関する。より詳しくは、給紙部より給紙された記録材（転写紙・静電記録紙・エレクトロファックス紙等）に適宜の作像原理・プロセス（転写方式或いは直接方式の電子写真プロセス・静電記録プロセス・磁気記録プロセス等）の作像手段にて所要の画像情報に対応した画像（未定着トナー像）を形成担持させ、該記録材を定着手段の第１の回転体と第２の回転体との間の定着部（ニップ部）に導入して挟持搬送させて記録材に画像を定着（加熱加圧定着、圧力定着等）させるレーザービームプリンタ・複写機等の画像形成装置に関する。 The present invention relates to an image forming apparatus. More specifically, an appropriate image forming principle / process (transfer method or direct type electrophotographic process / electrostatic recording) on a recording material (transfer paper, electrostatic recording paper, electrofax paper, etc.) fed from a paper feeding unit. The image (unfixed toner image) corresponding to the required image information is formed and supported by the image forming means of the process, magnetic recording process, etc., and the recording material is used as the first rotating body and the second rotating body of the fixing means. The present invention relates to an image forming apparatus such as a laser beam printer and a copying machine which is introduced into a fixing portion (nip portion) between the two and is conveyed while being nipped and conveyed to fix an image on a recording material (heating pressure fixing, pressure fixing, etc.).
例えば、転写式電子写真方式を利用した画像形成装置では、感光体ドラム等の像担持体上に形成されたトナー像を記録材上の転写した後に、定着手段としての加熱定着装置によって未定着トナー像を記録材に加熱定着させて画像形成物（コピー、プリント）を得ている。 For example, in an image forming apparatus using a transfer type electrophotographic system, a toner image formed on an image carrier such as a photosensitive drum is transferred onto a recording material, and then unfixed toner by a heat fixing device as a fixing unit. The image is heated and fixed on the recording material to obtain an image formed product (copy, print).
加熱定着装置としては、例えば熱ローラ方式のものが用いられる。熱ローラ方式の加熱定着装置（以下、定着装置と記す）は、ハロゲンヒータ等の加熱体（発熱体）を内包し、該加熱体で加熱されて所定の定着温度に加熱温調維持される熱ローラ（以下、定着ローラと記す）と、該熱ローラと並行に配置された該熱ローラと相互圧接する弾性加圧ローラ（以下、加圧ローラと記す）とを基本構成とし、該ローラ対を回転させ、該ローラ対の相互圧接部である定着ニップ部（加熱ニップ部）に未定着トナー画像を形成担持させた記録材を導入して挟持搬送させて定着ローラの熱と、定着ニップ部の加圧力にて未定着トナー像を記録材面に加熱加圧定着させるものである。一般に、定着ローラは未定着トナー画像の加熱溶融効率を考慮して記録材の未定着トナー像担持面側に配置され、加圧ローラは未定着トナー像担持面と反対面側に配置される。 As the heat fixing device, for example, a heat roller type is used. A heat roller type heat fixing device (hereinafter referred to as a fixing device) includes a heating element (heating element) such as a halogen heater, and is heated by the heating element so as to maintain the heating temperature at a predetermined fixing temperature. A roller (hereinafter referred to as a fixing roller) and an elastic pressure roller (hereinafter referred to as a pressure roller) that are in pressure contact with the heat roller arranged in parallel with the heat roller are basically configured. The recording material on which an unfixed toner image is formed and supported is introduced into the fixing nip portion (heating nip portion), which is the mutual pressure contact portion of the roller pair, and is nipped and conveyed to heat the fixing roller and the fixing nip portion. An unfixed toner image is fixed to the surface of the recording material by heating and pressing with pressure. In general, the fixing roller is disposed on the unfixed toner image carrying surface side of the recording material in consideration of the heating and melting efficiency of the unfixed toner image, and the pressure roller is disposed on the surface opposite to the unfixed toner image carrying surface.
上記の電子写真方式を利用した画像形成装置では、例えば特許文献１および２等に開示されているように、記録材の一面のみに、もしくは記録材の両面（一面および二面）に画像を形成できるものがある。記録材の一面のみに画像を形成する場合（以下、片面画像形成モードと記す）、感光体ドラム上に形成されたトナー像を転写手段により記録材の一面に転写し、その記録材を定着装置のニップ部に通紙させて未定着トナー像を該記録材の一面に加熱定着させる。記録材の両面に画像を形成する場合（以下、両面画像形成モードと記す）には、上記の定着装置を通過した一方面画面形成済みの記録材を感光体ドラムにスイッチバック反転搬送して該感光体ドラム上に形成されたトナー像を転写手段により記録材の二面目に転写し、その記録材を定着装置のニップ部に通紙させて未定着トナー像を該記録材の二面目に加熱定着させる。 In the image forming apparatus using the above-described electrophotographic method, as disclosed in Patent Documents 1 and 2, for example, an image is formed only on one surface of the recording material or on both surfaces (one surface and two surfaces) of the recording material. There is something you can do. When an image is formed on only one surface of the recording material (hereinafter referred to as a single-sided image forming mode), the toner image formed on the photosensitive drum is transferred to one surface of the recording material by a transfer unit, and the recording material is fixed to the fixing device. Then, the unfixed toner image is heated and fixed on one surface of the recording material. When images are formed on both sides of the recording material (hereinafter referred to as a double-sided image forming mode), the recording material on which the one-side screen is formed that has passed through the fixing device is switched back and conveyed to the photosensitive drum. The toner image formed on the photosensitive drum is transferred to the second surface of the recording material by the transfer means, and the recording material is passed through the nip portion of the fixing device to heat the unfixed toner image on the second surface of the recording material. Let it settle.
上記した電子写真方式を利用した画像形成装置では、未定着トナー像を定着する際に、一般に、片面画像形成モード時には記録材搬送方向に対して先端部に約２〜５ｍｍの余白（以下、先端余白と呼ぶ）を形成する必要があり、両面画像形成モード時には記録材搬送方向に対して後端部に約２〜５ｍｍの余白（以下、後端余白と呼ぶ）を形成する必要がある。先端余白は、定着装置の定着ローラから未定着トナー像をのせた記録材の分離を促すために、記録材先端部に設ける必要がある。次に後端余白の必要性について簡単に述べる。両面画像形成時には一面目画像定着後、両面搬送経路（スイッチバック反転搬送路）をとおり反転搬送されて二面目定着時には一面目トナー像が加圧ローラ側で且つ後端余白側が記録材搬送方向先端側になるために、後端余白を設けることにより加圧ローラからの分離を促しているのである。
上記したように従来の電子写真方式を利用した画像形成装置では、記録材先端部および記録材後端部に約２〜５ｍｍの余白を形成するが、これによって以下のような問題が発生する可能性がある。 As described above, in the image forming apparatus using the conventional electrophotographic method, a margin of about 2 to 5 mm is formed at the leading end portion of the recording material and the trailing end portion of the recording material, which may cause the following problems. There is sex.
電子写真方式を利用した画像形成装置が例えば複写機の場合には、片面画像形成モード時において、記録材先端部に画像情報を有する原稿を複写する際などに、記録材先端に余白部があることによって画像情報の一部が欠損する。例えば、記録材先端に対応した画像情報を有する原稿を複写する際などに、画像情報を欠損させないようにすると、先端余白部がなくなることになり、上述したとおりトナー像を乗せた記録材を定着ローラから分離を促していた作用が少なくなり、記録材先端部上に担持したトナー量が多い場合には、定着ローラに記録材が巻きつく場合がある。 When the image forming apparatus using the electrophotographic method is, for example, a copying machine, there is a blank portion at the leading end of the recording material when copying a document having image information at the leading end of the recording material in the single-sided image forming mode. As a result, part of the image information is lost. For example, when copying a document having image information corresponding to the front end of the recording material, if the image information is not lost, the margin at the front end is eliminated, and the recording material with the toner image is fixed as described above. When the action that promotes separation from the roller is reduced and the amount of toner carried on the leading end of the recording material is large, the recording material may be wound around the fixing roller.
この問題はニップ出口近傍に定着ローラ表面に一定の加圧力によって接触させた分離爪を設けることにより、もしも記録材が定着ローラに巻きついた場合においても記録材の先端が分離爪によってはがされることによって回避される。しかしながら、分離爪は常時一定の加圧力によって定着ローラ表面に当接しているために、定着ローラの表面に摺擦傷が発生するようになり、摺擦傷が顕著になってくるとその部分が定着不良になり光沢ムラ等の画像不良として表れてくる。 This problem is caused by providing a separation claw that is brought into contact with the surface of the fixing roller with a constant pressure near the nip outlet, so that even if the recording material is wound around the fixing roller, the leading edge of the recording material is peeled off by the separation claw. Can be avoided. However, since the separation claw is always in contact with the surface of the fixing roller with a constant applied pressure, the surface of the fixing roller is rubbed. And appear as image defects such as uneven gloss.
同様に、両面画像形成モード時において、記録材後端に対応した画像情報を有する原稿を複写する際などに画像情報を欠損させないようにすると、記録材後端余白部がなくなるため、一面目定着後、反転搬送されて二面目定着時には、加圧ローラ側に一面目画像後端部から定着ニップに進入するようになる。その結果、余白によって分離を促していた作用がすくなくなり、後端余白部にのっているトナー量が多くなると加圧ローラに巻きつく問題が生じる。加圧ローラ表面に一定の加圧力によって常時分離爪を当接することにより上記問題は回避できるが、加圧ローラ摺擦傷による画像不良の問題が生じる。 Similarly, in the double-sided image formation mode, if image information is not lost when copying a document having image information corresponding to the recording material trailing edge, the recording material trailing edge margin is eliminated, so the first surface fixing is performed. After that, when the second surface is fixed by being reversed and conveyed, the pressure roller side enters the fixing nip from the rear end portion of the first surface image. As a result, the effect of promoting the separation by the margins becomes scarce, and when the amount of toner on the trailing edge margin increases, there arises a problem of winding around the pressure roller. The above problem can be avoided by always contacting the separation claw with a constant pressure on the surface of the pressure roller, but there is a problem of image defects due to the pressure roller sliding abrasion.
本発明は上記問題に鑑みてなされたものであり、その目的は、記録材の片面画像形成モード時の搬送方向先端部、及び記録材の両面画像形成モード時の二面目の搬送方向後端部について画像の欠損および巻きつきを防止でき、画像不良の発生をも回避できる画像形成装置を提供することにある。 SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to provide a leading end in the transport direction in the single-sided image forming mode of the recording material and a trailing end in the transport direction of the second side in the double-sided image forming mode of the recording material It is an object of the present invention to provide an image forming apparatus capable of preventing image loss and wrapping and avoiding image defects.
本発明は下記の構成を特徴とする画像形成装置である。 The present invention is an image forming apparatus having the following configuration.
（１）記録材上に未定着トナー像を形成する作像手段と、ニップ部を形成し該ニップ部で前記記録材を挟持搬送して未定着トナー像を加熱定着する、記録材の未定着トナー像担持面側に対向する第１の回転体とその反対面側に対向する第２の回転体とを具備した定着手段と、を有し、記録材の一面に画像を形成する片面画像形成モードと、前記定着手段を通過した一方面画像形成済みの記録材の二面に未定着トナー像を形成し前記定着手段で加熱定着させる両面画像形成モードと、を選択できる画像形成装置において、
前記第１の回転体に接離動作する第１の記録材分離部材と、
前記第２の回転体に接離動作する第２の記録材分離部材と、
前記第１の記録材分離部材を前記第１の回転体に対して接離動作させる第１の動作手段と、
前記第２の記録材分離部材を前記第２の回転体に対して接離動作させる第２の動作手段と、
前記作像手段において記録材上に画像形成する際に記録材搬送方向先端余白幅及び記録材搬送方向後端余白幅を可変設定できる余白幅可変設定手段と、
前記余白幅可変設定手段で設定した記録材搬送方向先端余白幅または記録材搬送方向後端余白幅に応じて、前記片面画像形成モードの定着実行時と前記両面画像形成モードの定着実行時においては前記第１の動作手段と前記第２の動作手段についてそれぞれ記録材分離部材を回転体に対して当接または離間の動作制御する制御手段と、
を有することを特徴とする画像形成装置。
(1) Image forming means for forming an unfixed toner image on a recording material, and an unfixed recording material in which a nip portion is formed and the recording material is sandwiched and conveyed by the nip portion to heat and fix the unfixed toner image A single-sided image forming apparatus comprising: a first rotating body facing the toner image carrying surface side; and a fixing unit having a second rotating body facing the opposite surface side, and forming an image on one surface of the recording material. In an image forming apparatus capable of selecting a mode and a double-sided image forming mode in which an unfixed toner image is formed on two surfaces of a recording material on which one-sided image is formed that has passed through the fixing unit and heated and fixed by the fixing unit.
A first recording material separating member that contacts and separates from the first rotating body;
A second recording material separating member that moves toward and away from the second rotating body;
First operating means for moving the first recording material separating member into and out of contact with the first rotating body;
Second operating means for moving the second recording material separating member into and out of contact with the second rotating body;
Margin width variable setting means capable of variably setting the leading edge margin width in the recording material conveyance direction and the trailing edge margin width in the recording material conveyance direction when forming an image on the recording material in the image forming means;
Depending on the leading-edge margin width in the recording material conveyance direction or the trailing-edge margin width in the recording material conveyance direction set by the margin width variable setting means, when fixing in the single-sided image formation mode and fixing in the double-sided image formation mode, Control means for controlling the contact or separation of the recording material separating member with respect to the rotating body with respect to the first operating means and the second operating means;
An image forming apparatus comprising:
（２）前記制御手段は、前記片面画像形成モードの定着実行時、または前記両面画像形成モードの一面目定着時においては、前記余白幅可変設定手段で設定された先端余白幅が規定幅以上の場合には前記第１の回転体に対して前記第１の記録材分離部材を離間させる方向に前記第１の動作手段を制御し、規定幅未満の場合には前記第１の回転体に対して前記第１の記録材分離部材を当接させる方向に前記第１の動作手段を制御し、前記第２の回転体に対して前記第２の記録材分離部材を離間させる方向に前記第２の動作手段を制御することを特徴とする（１）に記載の画像形成装置。 (2) When the fixing in the single-sided image forming mode is performed or the first side fixing in the double-sided image forming mode is performed, the control unit has a leading margin width set by the margin width variable setting unit equal to or larger than a specified width. In this case, the first operation means is controlled in a direction in which the first recording material separating member is separated from the first rotating body. The first operating means is controlled in the direction in which the first recording material separating member is brought into contact, and the second recording material is separated in the direction in which the second recording material separating member is separated from the second rotating body. The image forming apparatus according to (1), wherein the operation unit is controlled.
（３）前記制御手段は、前記両面画像形成モードの二面目定着時においては、一面目の画像形成時に前記余白幅可変設定手段で設定された後端余白幅が規定幅以上の場合には前記第２の回転体に対して前記第２の記録材分離部材を離間させる方向に前記第２の動作手段を制御し、規定幅未満の場合には前記第２の回転体に対して前記第２の記録材分離部材を当接させる方向に前記第２の動作手段を制御することを特徴とする（２）に記載の画像形成装置。 (3) In the second-side fixing in the double-sided image formation mode, the control unit determines that the rear end margin width set by the margin width variable setting unit at the time of image formation on the first side is equal to or greater than a specified width. The second operating means is controlled in a direction in which the second recording material separating member is separated from the second rotating body. When the second operating means is less than a specified width, the second operating body is controlled with respect to the second rotating body. The image forming apparatus according to (2), wherein the second operating unit is controlled in a direction in which the recording material separating member is abutted.
（４）前記第２の回転体に対して前記第２の記録材分離部材を当接させるタイミングは一面目定着から二面目定着直前までの間とすることを特徴とする（３）に記載の画像形成装置。 (4) The timing of bringing the second recording material separating member into contact with the second rotating body is from the first side fixing to immediately before the second side fixing. Image forming apparatus.
（５）通紙使用される記録材の種類に応じて、前記先端余白幅の規定幅及び前記後端余白幅の規定幅が変更されることを特徴とする（２）から（４）の何れかに記載の画像形成装置。 (5) The specified width of the leading edge margin width and the specified width of the trailing edge margin width are changed according to the type of recording material used for passing paper. An image forming apparatus according to claim 1.
（６）環境に応じて、前記先端余白幅の規定幅及び前記後端余白幅の規定幅が変更されることを特徴とする（２）から（４）の何れかに記載の画像形成装置。 (6) The image forming apparatus according to any one of (2) to (4), wherein the specified width of the leading edge margin width and the specified width of the trailing edge margin width are changed according to an environment.
（７）前記余白設定手段は、画像形成装置本体に設けられた操作部からの設定情報に応じて余白幅を設定することを特徴とする（１）から（６）の何れかに記載の画像形成装置。 (7) The image according to any one of (1) to (6), wherein the margin setting unit sets a margin width in accordance with setting information from an operation unit provided in the main body of the image forming apparatus. Forming equipment.
即ち、余白幅可変設定手段で記録材搬送方向先端余白幅または記録材搬送方向後端余白幅が設定され、制御手段はその設定された記録材搬送方向先端余白幅または記録材搬送方向後端余白幅に応じて、片面画像形成モードの定着実行時と両面画像形成モードの定着実行時においては第１の動作手段と第２の動作手段についてそれぞれ記録材分離部材を回転体に対して当接させる方向または離間させる方向に動作制御するので、記録材の片面画像形成モード時における搬送方向先端部、及び記録材の両面画像形成モード時における二面目の搬送方向後端部について画像の欠損および巻きつきを防止でき、それぞれの記録材分離部材による回転体摺擦傷に伴う画像不良の発生をも回避できる。 In other words, the margin width variable setting means sets the leading margin width in the recording material conveyance direction or the trailing margin width in the recording material conveyance direction, and the control means sets the leading margin width in the recording material conveyance direction or the trailing margin in the recording material conveyance direction. Depending on the width, the recording material separating member is brought into contact with the rotating body for each of the first operating means and the second operating means during the fixing in the single-sided image forming mode and the fixing in the double-sided image forming mode. Since the movement control is performed in the direction of moving or separating, the leading edge of the recording material in the single-sided image forming mode and the trailing edge of the recording material in the double-sided image forming mode of the second side in the transporting direction are missing and wrapped. It is possible to prevent the occurrence of image defects due to the rotating body rubbing scratches by the respective recording material separating members.
以下、本発明を実施するための最良の形態を添付図面に従って詳しく説明する。 Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.
（１）画像形成装置例
図１は本実施例の画像形成装置の概略構成模型図であり、図２は画像形成装置の制御ブロック図である。
(1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration model diagram of an image forming apparatus of this embodiment, and FIG. 2 is a control block diagram of the image forming apparatus.
本例に示す画像形成装置はデジタル方式のコピー機（複写機）であり、記録材の片面のみに画像を形成する片面画像形成、及び記録材の両面に画像を形成する両面画像形成が可能な構成とされる。 The image forming apparatus shown in this example is a digital type copying machine (copier), which can perform single-sided image formation that forms an image on only one side of a recording material and double-sided image formation that forms an image on both sides of a recording material. It is supposed to be configured.
図１において、Ａは画像形成装置本体（以下、装置本体と記す）、Ｂは装置本体Ａの上に搭載したイメージリーダーである。 In FIG. 1, A is an image forming apparatus main body (hereinafter referred to as an apparatus main body), and B is an image reader mounted on the apparatus main body A.
イメージリーダーＢは、図２に示されるように、原稿１に対して図示しない照明ランプから光が照射された後、該原稿から反射した光はコリメータレンズ２を経てＣＣＤ３に入射される。ＣＣＤ３はその入射光に応じたアナログの電気信号を画像信号処理回路４に出力し、該画像信号処理回路４はアナログの電気信号をデジタルの画像信号に変換処理する。 As shown in FIG. 2, the image reader B is irradiated with light from an illumination lamp (not shown) on the document 1, and then the light reflected from the document enters the CCD 3 through the collimator lens 2. The CCD 3 outputs an analog electric signal corresponding to the incident light to the image signal processing circuit 4, and the image signal processing circuit 4 converts the analog electric signal into a digital image signal.
画像信号処理回路４によってデジタル変換処理された画像信号は、先端余白幅及び後端余白幅設定部（以下、余白幅設定部と記す）５に出力され、該余白幅設定部によって記録材の先端余白幅及び後端余白幅に対応する画像信号とされた後、ＲＯＭやＲＡＭなどのメモリ６に一度格納され、この後、後述の感光体ドラム２０に対する露光器としてのレーザースキャナーＣのレーザ駆動回路７に送られるようになっている。そして、レーザ駆動回路７は、この画像信号に基づきレーザ発振器８を駆動してレーザ光Ｌを発光させるようにしている。 The image signal digitally converted by the image signal processing circuit 4 is output to a leading edge margin width and trailing edge margin width setting unit (hereinafter, referred to as a margin width setting unit) 5, and the margin width setting unit outputs the leading edge of the recording material. The image signal corresponding to the margin width and the trailing edge margin width is stored once in the memory 6 such as ROM or RAM, and then a laser drive circuit of a laser scanner C as an exposure unit for the photosensitive drum 20 described later. 7 to be sent. The laser drive circuit 7 drives the laser oscillator 8 based on this image signal to emit the laser light L.
このようにして発光した画像信号（画像データ）に対応するレーザ光Ｌはポリゴンミラー９、レンズ１０、ミラー１１を介して作像手段としての作像部Ｄの感光体ドラム２０の表面に照射されるようになっている。 The laser beam L corresponding to the image signal (image data) emitted in this way is irradiated onto the surface of the photosensitive drum 20 of the image forming unit D as an image forming unit through the polygon mirror 9, the lens 10, and the mirror 11. It has become so.
作像部Ｄは電子写真作像機構であり、像担持体としての電子写真感光体ドラム２０を有し、その回りに一次帯電器２１、現像装置２２、二次帯電器２３、クリーニング装置２４などの電子写真プロセス機器が配置されている。感光体ドラム２０は、ＯＰＣ、アモルファスＳｅ、アモルファスＳｉ等の感光材料をアルミニウムやニッケル等のシリンダ状の基板上に形成して構成されている。 The image forming unit D is an electrophotographic image forming mechanism, and has an electrophotographic photosensitive drum 20 as an image carrier, around which a primary charger 21, a developing device 22, a secondary charger 23, a cleaning device 24, and the like. The electrophotographic process equipment is arranged. The photosensitive drum 20 is configured by forming a photosensitive material such as OPC, amorphous Se, or amorphous Si on a cylindrical substrate such as aluminum or nickel.
Ｅは定着手段としての定着装置であり、第１の回転体としての定着ローラ４０と、これに加圧された第２の回転体としての加圧ローラ４１とで記録材を挟持搬送する圧接部（以下、ニップ部と記す）Ｎを形成している。定着装置Ｄの構成については次の（２）項で説明する。 E is a fixing device as a fixing unit, and a pressure contact portion that sandwiches and conveys a recording material by a fixing roller 40 as a first rotating body and a pressure roller 41 as a second rotating body pressed against the fixing roller 40. N (hereinafter referred to as a nip portion) is formed. The configuration of the fixing device D will be described in the next section (2).
Ｆは両面画像形成の際に使用されるスイッチバック反転搬送機構であり、定着装置Ｄの出口側からフラッパ２８を介して記録材を先端側から搬入する搬入路２９ａと、その記録材を後端側から取り込んで表裏を反転させて後述のシートパス３４に送り出す反転搬送路２９ｂとを有する構成とされる。搬送路２９ａ及び反転搬送路２９ｂには再給紙ローラ２９ｃ・２９ｄが所定の位置に配置されている。 F is a switchback reversal conveyance mechanism used for double-sided image formation, and includes a carry-in path 29a for carrying the recording material from the front end side through the flapper 28 from the exit side of the fixing device D, and the rear end of the recording material. A reversing conveyance path 29b that takes in from the side, reverses the front and back, and sends the sheet to a sheet path 34 described later is provided. Refeed rollers 29c and 29d are disposed at predetermined positions in the transport path 29a and the reverse transport path 29b.
次に本例の画像形成装置の動作を説明する。 Next, the operation of the image forming apparatus of this example will be described.
感光体ドラム２０は矢印の反時計方向に所定のプロセススピードで回転駆動され、その表面は帯電器２１によって一様に、例えば−７００Ｖに帯電され、この後、原稿に対応した画像露光であるレーザ光Ｌが感光体ドラム上に照射され、これにより感光体ドラム上に静電潜像が形成される。 The photosensitive drum 20 is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined process speed. The surface of the photosensitive drum 20 is uniformly charged to, for example, −700 V by a charger 21, and then a laser which is image exposure corresponding to an original. The light L is irradiated onto the photosensitive drum, whereby an electrostatic latent image is formed on the photosensitive drum.
次に、この静電潜像が現像装置２２によって現像されてトナー像として顕像化される。現像方法としては、ジャンピング現像法等が用いられ、イメージ露光と反転現像との組み合わせで用いられることが多い。本実施例では現像剤として絶縁性一成分トナーを用いた現像装置である。 Next, the electrostatic latent image is developed by the developing device 22 and visualized as a toner image. As a developing method, a jumping developing method or the like is used, and it is often used in combination with image exposure and reversal development. In this embodiment, the developing device uses an insulating one-component toner as a developer.
一方、記録材カセット３０、あるいは手差し給紙トレイ３１に積載収納させた記録材（以下、転写材と記す）Ｐが給紙ローラ３２の回転動作によって給送され、分離ローラ対３３で１枚分離給送され、シートパス３４を通ってレジストローラ対３５に給送される。なお、手差し給紙トレイ３１は最小給紙サイズものから最大給紙サイズ間の任意のサイズの転写材Ｐを収納、給紙することができるようになっている。 On the other hand, a recording material (hereinafter referred to as a transfer material) P stacked and stored in the recording material cassette 30 or the manual paper feed tray 31 is fed by the rotation operation of the paper feed roller 32 and separated by the separation roller pair 33. Then, the sheet is fed to the registration roller pair 35 through the sheet path 34. The manual paper feed tray 31 can store and feed a transfer material P having an arbitrary size between the minimum paper feed size and the maximum paper feed size.
給送された転写材Ｐは、レジストローラ対３５によって、感光体ドラム２０の表面に形成されたトナー像と同期を取り、感光体ドラム２０と二次帯電器２３とで形成される転写部に供給される。転写部において、感光体ドラム２０上のトナー像は不図示の電源による転写バイアスの作用で転写材Ｐの片面（表面）に静電転写される。 The transferred transfer material P is synchronized with the toner image formed on the surface of the photosensitive drum 20 by the registration roller pair 35 and is transferred to a transfer portion formed by the photosensitive drum 20 and the secondary charger 23. Supplied. In the transfer portion, the toner image on the photosensitive drum 20 is electrostatically transferred to one side (front surface) of the transfer material P by the action of a transfer bias by a power source (not shown).
ところで、本実施例に係るコピー機は、感光体ドラム２０にレーザ光を照射して電位が下がった所を現像するいわゆる反転現像方式のものであり、このような方式のものの場合には、画像露光を行わないことで画像露光部周囲に余白が形成される。即ち、仮にベタ黒画像を出力する時にも転写材Ｐの周囲部分にはレーザ露光はしないので現像されずに余白ができる。 By the way, the copying machine according to the present embodiment is of a so-called reversal developing system that develops a portion where the potential is lowered by irradiating the photosensitive drum 20 with a laser beam. By not performing exposure, a margin is formed around the image exposure portion. That is, even when a solid black image is output, the peripheral portion of the transfer material P is not exposed to laser light, so that a blank is formed without being developed.
トナー像が片面に転写された転写材Ｐは、分離帯電器２５による帯電バイアスの作用によって感光体ドラム面から分離された後、定着装置Ｅの定着ローラ４０と加圧ローラ４１間のニップ部Ｎに搬送される。そして、転写材Ｐはニップ部Ｎで加熱加圧されて未定着トナー像の定着を受けることにより片面に画像形成が行われる。 The transfer material P on which the toner image has been transferred to one side is separated from the surface of the photosensitive drum by the action of the charging bias by the separation charger 25, and then the nip N between the fixing roller 40 and the pressure roller 41 of the fixing device E. To be transported. Then, the transfer material P is heated and pressed at the nip portion N to receive an unfixed toner image, thereby forming an image on one side.
片面画像形成時には、定着装置Ｅにより片面にトナー像が定着された転写材Ｐは、そのまま排紙ローラ３６の回転動作によって排紙トレイ３７に排出される。 At the time of single-sided image formation, the transfer material P on which the toner image is fixed on one side by the fixing device E is discharged as it is to the paper discharge tray 37 by the rotation operation of the paper discharge roller 36.
一方、両面画像形成時には、定着装置Ｅにより一面目にトナー像が定着された転写材Ｐは、フラッパ２８の揺動動作によって搬送方向先端側からスイッチバック反転搬送機構Ｆの搬入路２９ａに搬入される。この際、転写材Ｐは、上下対の再給紙ローラ２９ｃの回転動作によって、転写材先端が反転搬送路２９ｂの合流部よりも下方に位置するまで搬入される。次に、転写材Ｐは、搬入路２９ａの再給紙ローラ２９ｃと反転搬送路２９ｂの再給紙ローラ２９ｄの回転動作によって、反転搬送路２９ｂに転写材後端側から搬送されてシートパス３４に送り出される。これによって、転写材Ｐの表裏が反転され、その反転姿勢のままレジストローラ対３５に給送される。 On the other hand, at the time of double-sided image formation, the transfer material P on which the toner image is fixed on the first side by the fixing device E is carried into the carry-in path 29a of the switchback reverse conveyance mechanism F from the leading end side in the conveyance direction by the swinging operation of the flapper 28. The At this time, the transfer material P is carried in until the leading edge of the transfer material is positioned below the joining portion of the reverse conveyance path 29b by the rotating operation of the pair of upper and lower refeed rollers 29c. Next, the transfer material P is conveyed from the rear end side of the transfer material to the reverse conveyance path 29b by the rotation operation of the refeed roller 29c in the carry-in path 29a and the refeed roller 29d in the reverse conveyance path 29b, and the sheet path 34. Sent out. As a result, the front and back of the transfer material P are reversed, and the transfer material P is fed to the registration roller pair 35 in the reversed posture.
給送された転写材Ｐは、再びレジストローラ３５によって、感光体ドラム２０の表面に形成されたトナー像と同期を取り、感光体ドラム２０と二次帯電器１５とで形成される転写部に供給される。転写部において、感光体ドラム２０上のトナー像は不図示の電源による転写バイアスの作用で転写材Ｐの二面目に静電転写される。 The transferred transfer material P is again synchronized with the toner image formed on the surface of the photosensitive drum 20 by the registration roller 35 and is transferred to a transfer portion formed by the photosensitive drum 20 and the secondary charger 15. Supplied. In the transfer unit, the toner image on the photosensitive drum 20 is electrostatically transferred onto the second surface of the transfer material P by the action of a transfer bias by a power source (not shown).
トナー像が二面目に転写された転写材Ｐは、分離帯電器２５による帯電バイアスの作用によって感光体ドラム面から分離され、定着装置Ｄの定着ローラ４０と加圧ローラ４１間のニップ部Ｎに搬送される。その転写材Ｐはニップ部Ｎで加熱加圧されて未定着トナー像の定着を受けることにより二面目に画像形成が行われ、その後、排紙ローラ３６の回転動作によって排紙トレイ３７に排紙される。 The transfer material P onto which the toner image has been transferred onto the second surface is separated from the surface of the photosensitive drum by the action of the charging bias by the separation charger 25, and reaches the nip N between the fixing roller 40 and the pressure roller 41 of the fixing device D. Be transported. The transfer material P is heated and pressed at the nip portion N to receive the fixing of the unfixed toner image, whereby image formation is performed on the second surface. Thereafter, the transfer material P is discharged onto the discharge tray 37 by the rotation operation of the discharge roller 36. Is done.
このように、両面画像形成時においては、転写材Ｐにおいて、未定着トナー像の一面目定着後、スイッチバック反転搬送機構Ｅによって反転搬送されて未定着トナー像の二面目定着時に、一面目トナー像が加圧ローラ４１側で、且つ後端側が転写材搬送方向先端側になる。 As described above, when the double-sided image is formed, after the first surface of the unfixed toner image is fixed on the transfer material P, the first-side toner is transported by the switchback reverse transport mechanism E and fixed on the second surface of the unfixed toner image. The image is on the pressure roller 41 side, and the rear end side is the front end side in the transfer material conveyance direction.
転写材分離後の回転感光体ドラム２０はその表面に残る転写残留トナーがクリーニング器２４により除去されて、繰り返して作像に供される。 After the transfer material is separated, the transfer residual toner remaining on the surface of the rotary photosensitive drum 20 is removed by the cleaning device 24 and is repeatedly used for image formation.
（２）定着装置
定着装置Ｅは、ヒートローラ方式の定着装置であり、図３に示されるように、互いに圧接して回転する定着ローラ４０とこれに加圧された加圧ローラ４１のニップ部Ｎに、未定着のトナー像ｔを担持した転写材Ｐを導入して挟持搬送させることで、未定着トナー像ｔを転写材Ｐの面に熱と圧力で定着させるものである。
(2) Fixing Device The fixing device E is a heat roller type fixing device, and as shown in FIG. 3, a nip portion between a fixing roller 40 that is pressed against each other and a pressure roller 41 pressed against the fixing roller 40 A transfer material P carrying an unfixed toner image t is introduced into N and is nipped and conveyed to fix the unfixed toner image t on the surface of the transfer material P with heat and pressure.
定着ローラ４０は、アルミニウム等の芯金４０ａの外周にシリコンゴム等の弾性層４０ｂを設け、更に該弾性層の表面にＰＦＡ・ＰＴＦＥ等のフッ素樹脂の離型層４０ｃを設け、芯金４０ａの内部に熱源としてのヒータ４０ｄを設けることで構成されている。 The fixing roller 40 is provided with an elastic layer 40b such as silicon rubber on the outer periphery of a core metal 40a such as aluminum, and further provided with a release layer 40c of fluororesin such as PFA / PTFE on the surface of the elastic layer. The heater 40d as a heat source is provided inside.
また加圧ローラ４１は、芯金４１ａと、前記芯金周りに同心一体にローラ状に成形被覆させたシリコーンゴム・フッ素ゴム・フッ素樹脂などの耐熱性弾性材層４１ｂと、前記弾性材層４１ｂの表面に設けられたＰＦＡ・ＰＴＦＥ等のフッ素樹脂の離型層４１ｃで構成され、不図示の加圧手段により定着ローラ４０に圧接して該定着ローラとの間にニップ部Ｎを形成する。 The pressure roller 41 includes a cored bar 41a, a heat-resistant elastic material layer 41b such as silicone rubber, fluororubber, and fluororesin that is concentrically and integrally formed around the cored bar, and the elastic material layer 41b. A release layer 41c of fluororesin such as PFA / PTFE provided on the surface of the toner is pressed, and is pressed against the fixing roller 40 by a pressing means (not shown) to form a nip portion N with the fixing roller.
加圧ローラ４１は矢示の反時計方向に所定の周速度で回転し、定着ローラ４０は加圧ローラ４１の回転によって矢示の時計方向に従動回転する。 The pressure roller 41 rotates in the counterclockwise direction indicated by the arrow at a predetermined peripheral speed, and the fixing roller 40 is driven to rotate in the clockwise direction indicated by the arrow as the pressure roller 41 rotates.
そして、定着ローラ４０のローラ表面には温度検知器としてのサーミスタ４２が当接され、該サーミスタで検出されたローラ表面温度に基づいて、不図示のヒータ駆動回路により定着ローラ表面温度が温調目標温度になるように定着ローラ４０が温調制御される。 A thermistor 42 as a temperature detector is brought into contact with the roller surface of the fixing roller 40. Based on the roller surface temperature detected by the thermistor, the fixing roller surface temperature is controlled by a heater driving circuit (not shown). The temperature of the fixing roller 40 is controlled so as to reach the temperature.
定着ローラ４０の表面温度が温調目標温度に達した後、未定着トナー像ｔを形成担持した転写材Ｐが定着装置Ｅのニップ部Ｎに搬送され、転写材Ｐがニップ部Ｎを挟持搬送されていく過程において未定着トナー像ｔが転写材Ｐの面に熱と圧力で定着される。 After the surface temperature of the fixing roller 40 reaches the temperature control target temperature, the transfer material P that forms and supports the unfixed toner image t is conveyed to the nip portion N of the fixing device E, and the transfer material P pinches and conveys the nip portion N. In the process, the unfixed toner image t is fixed on the surface of the transfer material P by heat and pressure.
（３）転写材分離機構の構成
図３において、４３は定着ローラ４０に巻きついた転写材Ｐを分離して排出するための定着分離機構であり、４４は加圧ローラ４１に巻きついた転写材Ｐを分離して排出するための加圧分離機構である。
(3) Configuration of Transfer Material Separation Mechanism In FIG. 3, 43 is a fixing separation mechanism for separating and discharging the transfer material P wound around the fixing roller 40, and 44 is a transfer wound around the pressure roller 41. This is a pressure separation mechanism for separating and discharging the material P.
定着分離機構４３は、定着ローラ４０の回転方向において、ニップ部Ｎと近接する下流側の位置で定着ローラ表面に所定角度をもって接離動作する第１の記録材分離部材としての分離爪４３ａを有し、該分離爪は装置本体Ａに軸４３ｂを介して揺動自在に保持された支持部材４３ｃの一端に回動自在に支持されている。分離爪４３ａの後端には引張りコイルバネ４３ｄが連結され、該コイルバネによって分離爪４３ａの先端が定着ローラ表面側に付勢されている。支持部材４３ｂの他端には第１の動作手段としてのソレノイド４３ｅが接続されており、該ソレノイドは図２に示される制御手段としての分離機構制御部１３によりオン・オフ制御される。支持部材４３ｃは、ソレノイド４３ｅがオフされた場合には実線にて示すように分離爪４３ａを定着ローラ表面から離間させるが、ソレノイド４３ｅがオンされると破線にて示すように軸４３ｂを中心に反時計方向に回動されて分離爪４３ａの先端を定着ローラ表面に押し付けるように当接させる。このとき、分離爪４３ａは、定着ローラ表面から受ける抗力が圧縮コイルバネ４３ｄの付勢力よりも大きい場合、該圧縮コイルバネの付勢力に抗して反時計方向に回動してローラ表面から退避するようになっている。これによって、分離爪４３ａを定着ローラ表面に当接させるときの当接力による定着ローラ表面への傷付きが適切に防止される。 The fixing separation mechanism 43 has a separation claw 43a as a first recording material separation member that moves toward and away from the surface of the fixing roller at a predetermined angle at a downstream position close to the nip portion N in the rotation direction of the fixing roller 40. The separation claw is rotatably supported at one end of a support member 43c that is swingably held by the apparatus main body A via a shaft 43b. A tension coil spring 43d is connected to the rear end of the separation claw 43a, and the tip of the separation claw 43a is urged toward the fixing roller surface by the coil spring. A solenoid 43e as a first operating means is connected to the other end of the support member 43b, and the solenoid is on / off controlled by a separation mechanism control section 13 as a control means shown in FIG. When the solenoid 43e is turned off, the support member 43c separates the separation claw 43a from the surface of the fixing roller as shown by a solid line, but when the solenoid 43e is turned on, the shaft 43b is centered as shown by a broken line. The tip of the separation claw 43a is brought into contact with the surface of the fixing roller by rotating counterclockwise. At this time, when the drag received from the surface of the fixing roller is larger than the biasing force of the compression coil spring 43d, the separation claw 43a rotates counterclockwise against the biasing force of the compression coil spring 43 and retracts from the roller surface. It has become. This appropriately prevents the fixing roller surface from being damaged by the contact force when the separation claw 43a is brought into contact with the fixing roller surface.
加圧分離機構４４も定着分離機構４３と同様な構成とされる。すなわち、加圧ローラ４１の回転方向において、ニップ部Ｎと近接する下流側の位置で加圧ローラ表面に所定角度をもって接離動作する第２の記録材分離部材としての分離爪４４ａを有し、該分離爪は装置本体Ａに軸４４ｂを介して揺動自在に保持された支持部材４４ｃの一端に回動自在に支持されている。分離爪４４ａの後端には引張りコイルバネ４４ｄが連結され、該コイルバネによって分離爪４４ａの先端が加圧ローラ表面側に付勢されている。支持部材４４ｂの他端には第２の動作手段としてのソレノイド４４ｅが接続されており、該ソレノイドは上記の分離機構制御部１３によりオン・オフ制御される。支持部材４４ｃは、ソレノイド４４ｅがオフされた場合には実線にて示すように分離爪４４ａを加圧ローラ表面から離間させるが、ソレノイド４４ｅがオンされると破線にて示すように軸４４ｂを中心に時計方向に回動されて分離爪４４ａの先端を加圧ローラ表面に押し付けるように当接させる。このとき、分離爪４４ａは、加圧ローラ表面から受ける抗力が圧縮コイルバネ４４ｄの付勢力よりも大きい場合、該圧縮コイルバネの付勢力に抗して時計方向に回動してローラ表面から退避するようになっている。これによって、分離爪４４ａを加圧ローラ表面に当接させるときの当接力による加圧ローラ表面への傷付きが適切に防止させる。 The pressure separation mechanism 44 is configured similarly to the fixing separation mechanism 43. That is, it has a separation claw 44a as a second recording material separation member that moves toward and away from the pressure roller surface at a predetermined angle at a downstream position close to the nip portion N in the rotation direction of the pressure roller 41, The separation claw is rotatably supported at one end of a support member 44c that is swingably held by the apparatus main body A via a shaft 44b. A tension coil spring 44d is connected to the rear end of the separation claw 44a, and the tip of the separation claw 44a is urged toward the pressure roller surface by the coil spring. A solenoid 44e as a second operating means is connected to the other end of the support member 44b, and the solenoid is on / off controlled by the separation mechanism control unit 13. When the solenoid 44e is turned off, the support member 44c separates the separation claw 44a from the surface of the pressure roller as shown by a solid line, but when the solenoid 44e is turned on, the support member 44c is centered on the shaft 44b as shown by a broken line. The tip of the separation claw 44a is brought into contact with the pressure roller surface by being rotated clockwise. At this time, if the drag received from the pressure roller surface is greater than the biasing force of the compression coil spring 44d, the separation claw 44a rotates clockwise against the biasing force of the compression coil spring to retract from the roller surface. It has become. This appropriately prevents the pressure roller surface from being damaged by the contact force when the separation claw 44a contacts the pressure roller surface.
（４）転写材の先端余白幅及び後端余白幅の設定構成
本例の画像形成装置は、図２に示されるように、コピー時にユーザーによって操作される操作パネル１２を装置本体に備えており、この操作パネル１２には、余白幅可変設定手段としての余白幅入力部１２ａと、片面画像形成モード１２ｂと、両面画像形成モード１２ｃと、紙種選択部１２ｄが表示される。片面画像形成モード１２ｂ及び両面画像形成モード１２ｃは転写材Ｐへの画像形成開始前に適宜選択される。余白幅入力部１２ａは、片面画像形成時に図４（ａ）に示される転写材Ｐの転写材搬送方向の先端余白幅ａを、もしくは両面画像形成時に同図（ｂ）に示される転写材Ｐの二面目の搬送方向後端余白幅ｂを手動で可変設定できるようになっている。紙種選択部１２ｄは転写材Ｐの種類を選択可能となっており、例えば、図７に示されるように、普通紙１、普通紙２、厚紙１〜厚紙３の５種類の中から１つ選択される。操作パネル１２では、片面画像形成モード１２ｂ及び両面画像形成モード１２ｃのモード選択信号Ｓａと、余白幅入力部１２ａで設定された先端余白幅ａ及び後端余白幅ｂに応じた設定値信号Ｓｂを余白幅設定部５に出力し、紙種選択部１２ｄの紙種信号Ｓｅを制御手段としての分離機構制御部１３に出力する。
(4) Configuration for setting the leading and trailing margin widths of the transfer material As shown in FIG. 2, the image forming apparatus of this example includes an operation panel 12 that is operated by the user at the time of copying. The operation panel 12 displays a margin width input unit 12a as a margin width variable setting unit, a single-sided image formation mode 12b, a double-sided image formation mode 12c, and a paper type selection unit 12d. The single-sided image forming mode 12b and the double-sided image forming mode 12c are appropriately selected before starting image formation on the transfer material P. The margin width input unit 12a uses the margin width a in the transfer material conveyance direction of the transfer material P shown in FIG. 4A when a single-sided image is formed, or the transfer material P shown in FIG. The rear end margin width b in the transport direction on the second side can be variably set manually. The paper type selection unit 12d can select the type of the transfer material P. For example, as shown in FIG. 7, one of the five types of plain paper 1, plain paper 2, and thick paper 1 to thick paper 3 is selected. Selected. In the operation panel 12, the mode selection signal Sa for the single-sided image forming mode 12b and the double-sided image forming mode 12c, and the set value signal Sb corresponding to the leading edge margin width a and the trailing edge margin width b set by the margin width input unit 12a. It outputs to the margin width setting part 5, and outputs the paper type signal Se of the paper type selection part 12d to the separation mechanism control part 13 as a control means.
余白幅設定部５では、操作パネル１２からのモード選択信号Ｓａに基づいて片面画像形成か両面画像形成かの判断を行う。片面画像形成と判断した場合、操作パネル１２から先端余白幅ａに応じた設定値信号Ｓｂを入力し、その設定値信号Ｓｂに基づき画像信号処理回路４からの画像信号を上記先端余白幅ａに対応する画像信号とする信号処理を実行してメモリ６に格納すると共に、該設定値信号Ｓｂを先端余白幅設定値Ｓａ１として分離機構制御部１３に出力する。両面画像形成と判断した場合には、操作パネル１２から後端余白幅ｂに応じた設定値信号Ｓｂを入力し、その設定値信号Ｓｂに基づき画像信号処理回路４からの画像信号を上記後端余白幅ｂに対応する画像信号とする信号処理を実行してメモリ６に格納すると共に、該設定値信号Ｓｂを後端余白幅設定値Ｓｂ１として分離機構制御部１３に出力する。 The margin width setting unit 5 determines whether single-sided image formation or double-sided image formation based on the mode selection signal Sa from the operation panel 12. When it is determined that single-sided image formation is performed, a setting value signal Sb corresponding to the leading edge margin width a is input from the operation panel 12, and the image signal from the image signal processing circuit 4 is set to the leading edge margin width a based on the setting value signal Sb. Signal processing for corresponding image signals is executed and stored in the memory 6, and the set value signal Sb is output to the separation mechanism control unit 13 as the leading edge margin width set value Sa1. When it is determined that double-sided image formation is performed, a setting value signal Sb corresponding to the trailing edge margin width b is input from the operation panel 12, and the image signal from the image signal processing circuit 4 is input to the trailing edge based on the setting value signal Sb. The signal processing for making an image signal corresponding to the margin width b is executed and stored in the memory 6, and the set value signal Sb is output to the separation mechanism control unit 13 as the rear end margin width set value Sb1.
分離機構制御部１３は、余白幅設定部５から先端余白幅設定値Ｓａ１及び後端余白幅設定値Ｓｂ１を入力し、該先端余白幅設定値に応じて、もしくは該後端余白幅設定値に応じて定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅを所定のタイミングで動作制御する。あるいは、操作パネル１２からの紙種信号Ｓｅに基づいて転写材Ｐの種類を判定し、該転写材に応じた上記の先端余白幅設定値Ｓａ１に応じて、もしくは後端余白幅設定値Ｓｂ１に応じて定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅを所定のタイミングで動作制御する。または、図２に示されるように、装置本体Ａ内において記録材カセット３０の実装位置に温度・湿度センサ５０を配設して、これで記録材カセット３０付近の温度・湿度を検知させて、上記の先端余白幅設定値Ｓａ１に応じて、もしくは後端余白幅設定値Ｓｂ１に応じて定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅを所定のタイミングで動作制御する。 The separation mechanism control unit 13 inputs the leading edge margin width setting value Sa1 and the trailing edge margin width setting value Sb1 from the margin width setting unit 5, and according to the leading edge margin width setting value or to the trailing edge margin width setting value. Accordingly, the operation of the solenoids 43e and 44e of the fixing separation mechanism 43 and the pressure separation mechanism 44 is controlled at a predetermined timing. Alternatively, the type of the transfer material P is determined based on the paper type signal Se from the operation panel 12, and the leading edge margin width setting value Sa1 corresponding to the transfer material or the trailing edge margin width setting value Sb1. Accordingly, the operation of the solenoids 43e and 44e of the fixing separation mechanism 43 and the pressure separation mechanism 44 is controlled at a predetermined timing. Alternatively, as shown in FIG. 2, a temperature / humidity sensor 50 is disposed at the mounting position of the recording material cassette 30 in the apparatus main body A so that the temperature / humidity near the recording material cassette 30 is detected. The operation of the solenoids 43e and 44e of the fixing separation mechanism 43 and the pressure separation mechanism 44 is controlled at a predetermined timing according to the leading edge margin width setting value Sa1 or according to the trailing edge margin width setting value Sb1.
分離機構制御部１３では、先端余白幅設定値Ｓａ１及び後端余白幅設定値Ｓｂ１の入力前はソレノイド４３ｅ・４４ｅをオフ状態に保持し、片面画像形成時に先端余白幅設定値Ｓａ１に応じて定着分離機構４３のソレノイド４３ｅを所定のタイミングでオン・オフ動作させ、両面画像形成時には後端余白幅設定値Ｓｂ１に応じて加圧分離機構４４のソレノイド４４ｅを所定のタイミングでオン・オフ動作させる。 The separation mechanism control unit 13 holds the solenoids 43e and 44e in an off state before inputting the leading edge margin width setting value Sa1 and the trailing edge margin width setting value Sb1, and fixing according to the leading edge margin width setting value Sa1 during single-sided image formation. The solenoid 43e of the separation mechanism 43 is turned on / off at a predetermined timing, and at the time of double-sided image formation, the solenoid 44e of the pressure separation mechanism 44 is turned on / off at a predetermined timing according to the trailing edge margin width setting value Sb1.
すなわち、
１）片面画像形成時においては、転写材Ｐの先端余白幅ａに応じた先端余白幅設定値Ｓａ１が０〜２ｍｍの範囲にある場合に、転写材Ｐの定着ローラ４０からの分離不良が発生する確率が高いと判断して、定着分離機構４３のソレノイド４３ｅを所定のタイミングでオン動作させる。従って、片面画像形成時における転写材Ｐの定着ローラ４０からの分離を保証できうる最低規定幅Ｍとして先端余白幅ａ＝２ｍｍを定着分離機構４３のソレノイド４３ｅのオン動作制御の判断基準としている。
That is,
1) At the time of single-sided image formation, when the leading edge margin width setting value Sa1 corresponding to the leading edge margin width a of the transfer material P is in the range of 0 to 2 mm, the transfer material P is poorly separated from the fixing roller 40. Therefore, the solenoid 43e of the fixing separation mechanism 43 is turned on at a predetermined timing. Therefore, the margin width a = 2 mm at the front end is defined as the minimum standard width M that can guarantee the separation of the transfer material P from the fixing roller 40 at the time of single-sided image formation.
２）両面画像形成時においては、転写材Ｐの1面目（１回目の画像形成）の後端余白幅が、１面目定着後スイッチバッグ機能によりスイッチバックして再度定着NIPに到達する際には加圧ローラ側では先端側になる。そのため、１面目（１回目の画像形成）の後端余白幅が、両面定着時の加圧ローラ分離に影響する。従って、一面目の後端余白幅に応じた後端余白幅設定値が２ｍｍを超える場合に、転写材Ｐの定着ローラ４０からの分離不良が発生する確率が低いと判断して、定着分離機構４３のソレノイド４３ｅをオフ状態に維持し、二面目の後端余白幅ｂに応じた後端余白幅設定値Ｓｂ１が０〜２ｍｍの範囲にある場合には、転写材Ｐの加圧ローラ４１からの分離不良が発生する確率は高いと判断して、加圧分離機構４４のソレノイド４４ｅを所定のタイミングでオン動作制御する。従って、両面画像形成時における転写材Ｐの加圧ローラ４１からの分離を保証できうる最低規定幅Ｎとして後端余白幅ｂ＝２ｍｍを加圧分離機構４４のソレノイド４４ｅのオン動作制御の判断基準としている。 2) During double-sided image formation, when the trailing edge margin width of the first side (first image formation) of the transfer material P is switched back by the switch bag function after fixing the first side and reaches the fixing NIP again. On the pressure roller side, it is the tip side. Therefore, the trailing edge margin width on the first side (first image formation) affects the pressure roller separation during double-sided fixing. Accordingly, when the rear end margin width setting value corresponding to the rear end margin width of the first surface exceeds 2 mm, it is determined that the probability of occurrence of a separation failure from the fixing roller 40 of the transfer material P is low, and the fixing separation mechanism When the solenoid 43e of 43 is kept in the OFF state and the rear end margin width setting value Sb1 corresponding to the rear end margin width b of the second surface is in the range of 0 to 2 mm, the pressure roller 41 of the transfer material P Therefore, the solenoid 44e of the pressure separation mechanism 44 is controlled to be turned on at a predetermined timing. Therefore, the criterion for determining the ON operation control of the solenoid 44e of the pressure separation mechanism 44 is that the trailing edge margin width b = 2 mm is set as the minimum specified width N that can guarantee the separation of the transfer material P from the pressure roller 41 during double-sided image formation. It is said.
上記のソレノイド４３ｅ・４４ｅをオン動作させるタイミングは図２に示される転写材検知センサ５１からの検知信号Ｓｃに基づいて行い、ソレノイド４３ｅ・４４ｅをオフ動作させるタイミングは同図に示される排紙センサ５２からの検知信号Ｓｄに基づいて行う。 The timing for turning on the solenoids 43e and 44e is based on the detection signal Sc from the transfer material detection sensor 51 shown in FIG. 2, and the timing for turning off the solenoids 43e and 44e is the paper discharge sensor shown in FIG. Based on the detection signal Sd from 52.
転写材検知センサ５１は、レジストローラ対３５と、感光体ドラム２０と二次帯電器２３間の転写部との間に配設され、そこで転写材Pの先端を検知して分離機構制御部１３に検知信号Ｓｃを出力する。排紙センサ５２は、定着分離機構４３及び加圧分離機構４４の転写材出口側に配設され、そこで転写材Pの先端を検知して分離機構制御部１３に検知信号Ｓｄを出力する。 The transfer material detection sensor 51 is disposed between the registration roller pair 35 and the transfer portion between the photosensitive drum 20 and the secondary charger 23, and detects the leading edge of the transfer material P there to detect the separation mechanism control portion 13. The detection signal Sc is output to The paper discharge sensor 52 is disposed on the transfer material outlet side of the fixing separation mechanism 43 and the pressure separation mechanism 44, and detects the leading edge of the transfer material P and outputs a detection signal Sd to the separation mechanism control unit 13.
（５）転写材分離機構の動作制御の説明
１）片面画像形成の場合
図５は、片面画像形成時に分離機構制御部１３で実行する定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅの動作制御を示すフローチャート図である。
(5) Description of Operation Control of Transfer Material Separation Mechanism 1) In Case of Single-sided Image Formation FIG. 5 shows solenoids 43e and 44e of the fixing / separation mechanism 43 and the pressure separation mechanism 44 executed by the separation mechanism control unit 13 at the time of single-sided image formation. It is a flowchart figure which shows the operation control.
Ｓ１では、定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅをオフ状態に保持しており、ソレノイド４３ｅ・４４ｅのオフ状態で余白幅設定部５から先端余白幅設定値Ｓａ１を入力する（Ｓ２）と、Ｓ３に進む。 In S1, the solenoids 43e and 44e of the fixing separation mechanism 43 and the pressure separation mechanism 44 are held in the off state, and the leading edge margin width setting value Sa1 is input from the margin width setting unit 5 in the off state of the solenoids 43e and 44e. (S2) and the process proceeds to S3.
Ｓ３では、先端余白幅設定値Ｓａ１が最低規定幅Ｍよりも大きいか否かを判断する。Ｓａ１＞ＭであればＳ４に進む。Ｓａ１＜ＭであればＳ８に進み、先端余白幅設定値Ｓａ１をクリア（消去）して、片面画像形成時の定着・加圧分離機構４３・４４の動作制御を終了する。 In S3, it is determined whether or not the leading edge margin width setting value Sa1 is larger than the minimum specified width M. If Sa1> M, the process proceeds to S4. If Sa1 <M, the process proceeds to S8, the leading edge margin width setting value Sa1 is cleared (erased), and the operation control of the fixing / pressure separation mechanisms 43 and 44 at the time of single-sided image formation ends.
Ｓ４では、転写材検知センサ５１から検知信号Ｓｃを入力すると、Ｓ５に進む。 In S4, when the detection signal Sc is input from the transfer material detection sensor 51, the process proceeds to S5.
Ｓ５では、定着分離機構４３のソレノイド４３ｅをオンすると、Ｓ６に進む。定着分離機構４３は、ソレノイド４３ｅがオンされることで、図３にて破線で示すように、支持部材４３ｃが軸４３ｂを中心に反時計方向に回動されて分離爪４３ａの先端を定着ローラ表面に当接させる。これによって、もしも転写材Ｐが先端余白幅ａの部分で定着ローラ４０に巻きついた状態のまま定着ローラ４０と共に回転するようになったとしても、定着ローラ表面に当接された分離爪４３ａにより転写材Ｐの搬送方向先端（先端余白部分）を定着ローラ表面から分離することができる。 In S5, when the solenoid 43e of the fixing separation mechanism 43 is turned on, the process proceeds to S6. When the solenoid 43e is turned on, the fixing separation mechanism 43 rotates the support member 43c counterclockwise about the shaft 43b as shown by a broken line in FIG. Contact the surface. As a result, even if the transfer material P rotates with the fixing roller 40 while being wound around the fixing roller 40 at the front end margin width a, the separation claw 43a abutted on the surface of the fixing roller causes the transfer material P to rotate with the fixing roller 40. It is possible to separate the transfer material P in the conveyance direction front end (front end margin) from the surface of the fixing roller.
Ｓ６では、排紙センサ５２から検知信号Ｓｄを入力すると、Ｓ７に進む。 In S6, when the detection signal Sd is input from the paper discharge sensor 52, the process proceeds to S7.
Ｓ７では、定着分離機構４３のソレノイド４３ｅをオフする。定着分離機構４３は、ソレノイド４３ｅがオフされることで、図３にて実線で示すように、支持部材４３ｃが軸４３ｂを中心に時計方向に回動されて分離爪４３ａの先端を定着ローラ表面から離間させる。Ｓ７において定着分離機構４３のソレノイド４３ｅをオフした後に、片面画像形成時の定着・加圧分離機構４３・４４の一連の動作制御を終了する。 In S7, the solenoid 43e of the fixing separation mechanism 43 is turned off. When the solenoid 43e is turned off, the fixing separation mechanism 43 rotates the support member 43c clockwise around the shaft 43b as shown by a solid line in FIG. Separate from. After the solenoid 43e of the fixing separation mechanism 43 is turned off in S7, a series of operation control of the fixing / pressure separation mechanisms 43 and 44 at the time of single-sided image formation is ended.
このように、ユーザーによって操作パネル１２の余白幅設定部１２ａで転写材Ｐの先端余白幅ａが設定され、その設定された先端余白幅ａの大きさに基づいて、未定着トナー像が定着された転写材Ｐが定着ローラ４０から分離不良しやすい状況下においてのみ、定着分離機構４３の分離爪４３ａを定着ローラ表面に対して当接させることができるので、転写材先端の画像の欠損を防止できると共に、転写材Ｐの定着ローラ４０への巻きつきを防止でき、分離爪４３ａによる定着ローラ摺擦傷に伴う画像不良の発生を回避できる。 As described above, the margin width setting unit 12a of the operation panel 12 sets the leading edge margin width a of the transfer material P by the user, and the unfixed toner image is fixed based on the set leading margin width a. Since the separation claw 43a of the fixing separation mechanism 43 can be brought into contact with the surface of the fixing roller only in a situation where the transfer material P is likely to be poorly separated from the fixing roller 40, it is possible to prevent image loss at the front end of the transfer material. In addition, it is possible to prevent the transfer material P from being wrapped around the fixing roller 40, and to avoid the occurrence of image defects due to the fixing roller sliding scratches by the separation claw 43a.
２）両面画像形成の場合
図６は、両面画像形成時に分離機構制御部１３で実行する定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅの動作制御を示すフローチャート図である。
2) Case of Double-Side Image Formation FIG. 6 is a flowchart showing the operation control of the solenoids 43e and 44e of the fixing / separation mechanism 43 and the pressure separation mechanism 44, which is executed by the separation mechanism control unit 13 when double-sided images are formed.
Ｓ１１〜Ｓ１８は転写材Ｐの一面目への画像形成時のソレノイド４３ｅ・４４ｅの動作制御を、Ｓ１９〜Ｓ２５は転写材Ｐの二面目への画像形成時のソレノイド４３ｅ・４４ｅの動作制御をそれぞれ示すものである。Ｓ１１〜Ｓ１７は上述の片面画像形成のＳ１〜Ｓ７と同じであるので説明を省略する。 S11 to S18 control the operation of the solenoids 43e and 44e when forming an image on the first surface of the transfer material P, and S19 to S25 control the operations of the solenoids 43e and 44e when forming an image on the second surface of the transfer material P, respectively. It is shown. Since S11 to S17 are the same as S1 to S7 in the above-described single-sided image formation, description thereof is omitted.
Ｓ１１〜Ｓ１８において、Ｓ１８で先端余白幅設定値Ｓａ１をクリアすると、両面画像形成時の定着・加圧分離機構４３・４４の動作制御を終了して、Ｓ１９に進む。 In S11 to S18, when the leading edge margin width setting value Sa1 is cleared in S18, the operation control of the fixing / pressure separation mechanisms 43 and 44 at the time of double-sided image formation is terminated, and the process proceeds to S19.
Ｓ１９では、定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅのオフ状態で余白幅設定部５から二面目の後端余白幅設定値Ｓｂ１を入力すると、Ｓ２０に進む。 In S19, when the trailing edge margin width setting value Sb1 of the second surface is input from the margin width setting unit 5 while the solenoids 43e and 44e of the fixing separation mechanism 43 and the pressure separation mechanism 44 are off, the process proceeds to S20.
Ｓ２０では、後端余白幅設定値Ｓｂ１が最低規定幅Ｎよりも大きいか否かを判断する。Ｓｂ１＞ＮであればＳ２１に進む。Ｓｂ１＜ＮであればＳ２５に進み、後端余白幅設定値Ｓｂ１をクリア（消去）して、両面画像形成時の定着・加圧分離機構４３・４４の動作制御を終了する。 In S20, it is determined whether or not the trailing edge margin width setting value Sb1 is larger than the minimum specified width N. If Sb1> N, the process proceeds to S21. If Sb1 <N, the process proceeds to S25, where the trailing edge margin width setting value Sb1 is cleared (erased), and the operation control of the fixing / pressure separation mechanisms 43 and 44 at the time of double-sided image formation ends.
Ｓ２１では、転写材検知センサ５２から検知信号Ｓｃを入力すると、Ｓ２２に進む。 In S21, when the detection signal Sc is input from the transfer material detection sensor 52, the process proceeds to S22.
Ｓ２２では、加圧分離機構４４のソレノイド４４ｅをオンすると、Ｓ２３に進む。加圧分離機構４４は、ソレノイド４４ｅがオンされることで、図３にて破線で示すように、支持部材４４ｃが軸４４ｂを中心に時計方向に回動されて分離爪４４ａの先端を加圧ローラ表面に当接させる。これによって、もしも転写材Ｐが後端余白幅ｂの部分で加圧ローラ４１に巻きついた状態のまま加圧ローラ４１と共に回転するようになったとしても、加圧ローラ表面に当接された分離爪４４ａにより転写材Ｐの搬送方向先端（後端余白部分）を加圧ローラ表面から分離することができる。 In S22, when the solenoid 44e of the pressure separation mechanism 44 is turned on, the process proceeds to S23. When the solenoid 44e is turned on, the pressurizing / separating mechanism 44 rotates the support member 44c clockwise around the shaft 44b as shown by the broken line in FIG. 3 to pressurize the tip of the separating claw 44a. Contact the roller surface. As a result, even if the transfer material P rotates with the pressure roller 41 while being wound around the pressure roller 41 at the rear margin width b, the transfer material P is brought into contact with the pressure roller surface. The separation claw 44a can separate the front end (rear end margin) of the transfer material P from the pressure roller surface.
Ｓ２３では、排紙センサ５２から検知信号Ｓｄを入力すると、Ｓ２４に進む。 In S23, when the detection signal Sd is input from the paper discharge sensor 52, the process proceeds to S24.
Ｓ２４では、加圧分離機構４４のソレノイド４４ｅをオフする。加圧分離機構４４は、ソレノイド４４ｅがオフされることで、図３にて実線で示すように、支持部材４４ｃが軸４４ｂを中心に反時計方向に回動されて分離爪４４ａの先端を加圧ローラ表面から離間させる。Ｓ２４において加圧分離機構４４のソレノイド４４ｅをオフした後に、両面画像形成時の定着・加圧分離機構４３・４４の一連の動作制御を終了する。 In S24, the solenoid 44e of the pressure separation mechanism 44 is turned off. When the solenoid 44e is turned off, the pressure separation mechanism 44 rotates the support member 44c counterclockwise about the shaft 44b as shown by the solid line in FIG. 3 to add the tip of the separation claw 44a. Separated from the pressure roller surface. After the solenoid 44e of the pressure separation mechanism 44 is turned off in S24, a series of operation control of the fixing / pressure separation mechanisms 43 and 44 at the time of double-sided image formation is ended.
このように、ユーザーによって操作パネル１２の余白幅設定部１２ａで転写材Ｐの後端余白幅ｂが設定され、その設定された後端余白幅ｂの大きさに基づいて、未定着トナー像が定着された転写材Ｐが加圧ローラ４１から分離不良しやすい状況下においてのみ、加圧分離機構４４の分離爪４４ａを加圧ローラ表面に対して当接させることができるので、転写材後端の画像の欠損を防止できると共に、転写材Ｐの加圧ローラ４１の巻きつきを防止でき、分離爪４４ａによる加圧ローラ摺擦傷に伴う画像不良の発生を回避できる。 As described above, the user sets the trailing edge margin width b of the transfer material P in the margin width setting section 12a of the operation panel 12, and the unfixed toner image is determined based on the set trailing edge margin width b. The separation claw 44a of the pressure separation mechanism 44 can be brought into contact with the surface of the pressure roller only in a situation where the fixed transfer material P is likely to be poorly separated from the pressure roller 41. Can be prevented, and the wrapping of the pressure roller 41 of the transfer material P can be prevented, so that it is possible to avoid the occurrence of image defects due to the pressure roller sliding scratches by the separation claw 44a.
実施例１では、転写材Ｐの種類に問わず、転写材Ｐの先端余白幅ａ及び後端余白幅ｂの最低規定幅Ｍ・Ｎを定めており、その最低規定幅Ｍ・Ｎと操作パネル１２で設定された余白幅ａ・ｂに応じて定着ローラ４０及び加圧ローラ４１に分離爪４３ａ・４４ａを当接・離間させていた。 In the first embodiment, regardless of the type of the transfer material P, the minimum specified width M · N of the leading edge margin width a and the trailing edge margin width b of the transfer material P is determined, and the minimum specified width M · N and the operation panel are determined. The separation claws 43a and 44a are brought into contact with and separated from the fixing roller 40 and the pressure roller 41 in accordance with the margin widths a and b set in FIG.
実施例２では、通紙される転写材Ｐの種類すなわち坪量の異なる複数の転写材Ｐに応じて、先端余白幅ａ及び後端余白幅ｂの最低規定幅を変更している。 In Example 2, the minimum prescribed width of the leading edge margin width a and the trailing edge margin width b is changed according to the types of transfer materials P to be passed, that is, a plurality of transfer materials P having different basis weights.
一般に、転写材Ｐの剛性が高い、いわゆる“紙のコシ”が強い場合は、転写材Ｐが定着ローラ４０及び加圧ローラ４１に巻きつく可能性は低くなる。特に剛性がある程度以上大きい厚紙では先端余白幅ａ及び後端余白幅ｂに依存せずローラからの分離不良は発生しなくなる。逆に転写材Ｐの剛性が低い“紙のコシ”が小さい場合は、定着ローラ４０及び加圧ローラ４１からの分離性が悪くなるために、先端余白幅ａ及び後端余白幅ｂは剛性の高い紙に比べて大きく取る必要がある。 Generally, when the rigidity of the transfer material P is high, that is, the so-called “paper stiffness” is strong, the possibility that the transfer material P is wound around the fixing roller 40 and the pressure roller 41 is low. In particular, for thick paper having a certain degree of rigidity, a separation failure from the roller does not occur regardless of the leading edge margin width a and the trailing edge margin width b. On the other hand, when the “stiffness of the paper” is low when the rigidity of the transfer material P is low, the separation from the fixing roller 40 and the pressure roller 41 deteriorates, and therefore the leading edge margin width a and trailing edge margin width b are rigid. It is necessary to take larger than high paper.
そこで、本例では、図１に示す分離機構制御部１３に、図７に示されるような紙種−最低規定幅設定テーブルＴ１を具備させ、片面画像形成時及び両面画像形成時において、該テーブルに基づき、コピー時に操作パネル１２の紙種選択部１２ｄから選択された転写材Ｐの種類、及び余白幅入力部１２ａから選択された先端余白幅ａや後端余白幅ｂに応じて、定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅのオン・オフ動作制御を行う。 Therefore, in this example, the separation mechanism control unit 13 shown in FIG. 1 is provided with a paper type-minimum prescribed width setting table T1 as shown in FIG. 7, and this table is used during single-sided image formation and double-sided image formation. Based on the type of the transfer material P selected from the paper type selection unit 12d of the operation panel 12 at the time of copying, and the leading edge margin width a and the trailing edge margin width b selected from the margin width input unit 12a. On / off operation control of the solenoids 43e and 44e of the mechanism 43 and the pressure separation mechanism 44 is performed.
紙種−最低規定幅設定テーブルＴ１において余白幅規定量が上記の最低規定幅Ｍ・Ｎに対応する。したがって、分離機構制御部１３では、片面画像形成時に、操作パネル１２からの紙種信号Ｓｅに基づいて転写材Ｐの種類を判定すると共に、余白幅設定部１２ａからの先端余白幅設定値Ｓａ１が当該転写材の種類に対応する余白幅規定量Ｍよりも大きいか否かを判断して、定着分離機構４３のソレノイド４３ｅをオン・オフ動作することで分離爪４３ａを定着ローラ４０に当接・離間させる。両面画像形成時には、操作パネル１２からの紙種信号Ｓｅに基づいて転写材Ｐの種類を判定する。そして、一面目画像形成時に、余白幅設定部１２ａからの先端余白幅設定値Ｓａ１が当該転写材の種類に対応する余白幅規定量Ｍよりも大きいか否かを判断して、定着分離機構４３のソレノイド４３ｅをオン・オフ動作することで分離爪４３ａを定着ローラ４０に当接・離間させる。二面目画像形成時には、余白幅設定部１２ａからの後端余白幅設定値Ｓｂ１が当該転写材の種類に対応する余白幅規定量Ｎよりも大きいか否かを判断して、加圧分離機構４４のソレノイド４４ｅをオン・オフ動作することで分離爪４４ａを加圧ローラ４１に当接・離間させる。 In the paper type-minimum prescribed width setting table T1, the margin width prescribed amount corresponds to the minimum prescribed width M · N. Therefore, the separation mechanism control unit 13 determines the type of the transfer material P based on the paper type signal Se from the operation panel 12 and forms the leading edge margin width setting value Sa1 from the margin width setting unit 12a during single-sided image formation. It is determined whether or not the margin width width amount M corresponding to the type of the transfer material is larger, and the solenoid 43e of the fixing / separating mechanism 43 is turned on / off to bring the separation claw 43a into contact with the fixing roller 40. Separate. At the time of double-sided image formation, the type of the transfer material P is determined based on the paper type signal Se from the operation panel 12. Then, when the first side image is formed, it is determined whether or not the leading edge margin width setting value Sa1 from the margin width setting section 12a is larger than a margin width prescribed amount M corresponding to the type of the transfer material, and the fixing separation mechanism 43 is determined. The separation claw 43a is brought into contact with and separated from the fixing roller 40 by turning on and off the solenoid 43e. At the time of forming the second side image, it is determined whether the trailing edge margin width setting value Sb1 from the margin width setting section 12a is larger than the margin width prescribed amount N corresponding to the type of the transfer material, and the pressure separation mechanism 44. The separation claw 44a is brought into contact with and separated from the pressure roller 41 by turning on / off the solenoid 44e.
よって、本例においても実施例１と同様の作用・効果を得ることができる。その他に、転写材Ｐにおいて坪量が１５０ｇを超える厚紙１及び２では、上記の余白幅入力部から選択された先端余白幅および後端余白幅が０ｍｍでも分離爪なしで転写材を定着ローラ４０及び加圧ローラ４１から分離できることから、不必要に分離爪をローラに当接させなくてもよいために、実施例１の効果をより向上させることが可能となる。 Therefore, also in this example, the same operations and effects as those in Example 1 can be obtained. In addition, for the thick papers 1 and 2 having a basis weight of more than 150 g in the transfer material P, the transfer material is fixed to the fixing roller 40 without separation claw even if the leading edge margin width and the trailing edge margin width selected from the margin width input portion are 0 mm. And since it is possible to separate from the pressure roller 41, the separation claw need not be brought into contact with the roller unnecessarily, so that the effect of the first embodiment can be further improved.
実施例１では転写材Ｐのおかれている環境に問わず、転写材Ｐの先端余白幅ａ及び後端余白幅ｂの最低規定幅Ｍ・Ｎを定めており、その最低規定幅Ｍ・Ｎと操作パネル１２で設定された余白幅ａ・ｂに応じて定着ローラ４０及び加圧ローラ４１に分離爪４３ａ・４４ａを当接・離間させていた。 In the first embodiment, regardless of the environment in which the transfer material P is placed, the minimum specified width M · N of the leading edge margin width a and the trailing edge margin width b of the transfer material P is determined. According to the margin widths a and b set on the operation panel 12, the separation claws 43a and 44a are brought into contact with and separated from the fixing roller 40 and the pressure roller 41, respectively.
実施例３では、環境に応じて、先端余白幅ａ及び後端余白幅ｂの最低規定幅を変更している。 In Example 3, the minimum prescribed widths of the leading edge margin width a and the trailing edge margin width b are changed according to the environment.
一般に、転写材がおかれている環境が高温高湿度条件になると、転写材中の水分量が増加し、いわゆる紙のコシが弱くなる。その結果、コシが弱くなった転写材Ｐが定着ローラ４０及び加圧ローラ４１に巻きつく可能性が高くなるのである。逆に低温低湿環境下では、転写材の水分量が小さいために紙のコシが強くなり、転写材Ｐが定着ローラ４０及び加圧ローラ４１に巻きつく可能性は著しく小さくなる。 In general, when the environment in which the transfer material is placed becomes a high temperature and high humidity condition, the amount of moisture in the transfer material increases and the so-called paper stiffness becomes weak. As a result, there is a high possibility that the transfer material P having weak stiffness will be wound around the fixing roller 40 and the pressure roller 41. On the other hand, in a low temperature and low humidity environment, the transfer material P becomes stiff due to the small moisture content of the transfer material, and the possibility that the transfer material P wraps around the fixing roller 40 and the pressure roller 41 is significantly reduced.
そこで、本例では、図１に示す分離機構制御部１３に、図８に示されるような高温高湿環境仕様の紙種−最低規定幅設定テーブルＴ２１と低温低湿環境仕様の紙種−最低規定幅設定テーブルＴ２２の二つのテーブルを具備させ、片面画像形成時及び両面画像形成時において、該各テーブルに基づき、コピー時に操作パネル１２の紙種選択部１２ｄから選択された転写材Ｐの種類、及び余白幅入力部１２ａから選択された先端余白幅ａや後端余白幅ｂに応じて、定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅのオン・オフ動作制御を行う。 Therefore, in this example, the separation mechanism control unit 13 shown in FIG. 1 has the high temperature and high humidity environment specification paper type-minimum specified width setting table T21 and the low temperature and low humidity environment specification paper type as shown in FIG. Two types of width setting table T22 are provided, and the type of transfer material P selected from the paper type selection unit 12d of the operation panel 12 at the time of copying based on the respective tables at the time of single-sided image formation and double-sided image formation, Further, on / off operation control of the solenoids 43e and 44e of the fixing separation mechanism 43 and the pressure separation mechanism 44 is performed according to the leading edge margin width a and the trailing edge margin width b selected from the margin width input unit 12a.
各紙種−最低規定幅設定テーブルＴ２１・Ｔ２２において余白幅規定量が上記の最低規定幅Ｍ・Ｎに対応する。したがって、分離機構制御部１３では、温度・湿度センサ５０からの出力信号Ｓｆに基づいて記録材カセット３０の実装位置の環境温度及び湿度を求め、その環境温度及び湿度に基づき高温高湿環境か若しくは低温低湿環境かを判定し、その判定結果に対応する紙種−最低規定幅設定テーブルを用いて、片面画像形成時および両万画像形成時に、実施例２と同様に、定着分離機構４３及び加圧分離機構４４のソレノイド４３ｅ・４４ｅをオン・オフ動作する。 In each paper type-minimum prescribed width setting table T21 / T22, the margin width prescribed amount corresponds to the above-mentioned minimum prescribed width M · N. Accordingly, the separation mechanism control unit 13 obtains the environmental temperature and humidity at the mounting position of the recording material cassette 30 based on the output signal Sf from the temperature / humidity sensor 50, and determines whether the high temperature and high humidity environment based on the environmental temperature and humidity. Using the paper type-minimum specified width setting table corresponding to the determination result, it is determined whether the environment is a low-temperature and low-humidity environment. The solenoids 43e and 44e of the pressure separation mechanism 44 are turned on / off.
よって、本例においても実施例１と同様の作用・効果を得ることができる。その他に、
上記の高温高湿環境仕様テーブルＴ２１では、転写材Ｐにおいて坪量が１５０gを超える厚紙２・３について余白幅入力部から選択された先端余白幅および後端余白幅が０mmでも分離爪なしで転写材が定着ローラ及び加圧ローラから分離でき、また低温低湿環境仕様テーブルＴ２２では、転写材Ｐにおいて坪量が１０５gを超える厚紙１〜３のついて余白幅入力部から選択された先端余白幅および後端余白幅が０mmでも分離爪なしで転写材が定着ローラ及び加圧ローラから分離できるために、分離爪を対応するローラに当接する必要がなくなることになる。
Therefore, also in this example, the same operations and effects as those in Example 1 can be obtained. Other,
In the high-temperature, high-humidity environment specification table T21, transfer is performed without separation claws even if the leading edge margin width and the trailing edge margin width selected from the margin width input section are 0 mm for thick paper 2 and 3 having a basis weight exceeding 150 g in the transfer material P. The material can be separated from the fixing roller and the pressure roller, and in the low temperature and low humidity environment specification table T22, the leading edge margin width and the rear edge selected from the margin width input portion of the thick paper 1 to 3 having a basis weight exceeding 105 g in the transfer material P Even if the end margin width is 0 mm, the transfer material can be separated from the fixing roller and the pressure roller without the separation claw, so that it is not necessary to contact the separation claw with the corresponding roller.
このように本実施例３では、環境に応じて先端余白幅及び後端余白幅の最低規定幅を変更することにより不必要に分離爪を当接することがなくなり、実施例１の効果をより向上させることが可能となる。 As described above, in the third embodiment, the separation pawl is not unnecessarily brought into contact by changing the minimum prescribed width of the leading edge margin width and the trailing edge margin width according to the environment, and the effect of the first embodiment is further improved. It becomes possible to make it.
［その他］
１）各実施例において、両面画像形成モードで分離爪４４ａを加圧ローラ４１に当接させるのは、転写材Ｐの二面目に未定着トナー像を定着させた後の加圧ローラ４１からの分離を保証するためであり、よって分離爪４４ａを加圧ローラ４１に当接させるタイミングは、最低限二面目定着直前であれば良い。例えば、本実施の形態で示したように、レジストローラ３５の直後に転写材検知センサー５１を設けて、一面目定着後、スイッチバック反転搬送機構Ｅによって反転搬送されて再度レジストローラ対３５を通り、上記転写材センサー５１が検知したタイミングで分離爪４４ａを加圧ローラ４１に当接させることにより、分離爪４４ａを加圧ローラ４１に当接する時間を短くでき、分離爪４４ａによる加圧ローラ摺擦傷に伴う画像不良の発生をより低減することが可能となる。
[Others]
1) In each embodiment, the separation claw 44a is brought into contact with the pressure roller 41 in the double-sided image forming mode because the unfixed toner image is fixed on the second surface of the transfer material P from the pressure roller 41. This is for assuring separation, and therefore, the timing for bringing the separation claw 44a into contact with the pressure roller 41 may be at least immediately before fixing the second surface. For example, as shown in the present embodiment, the transfer material detection sensor 51 is provided immediately after the registration roller 35, and after the first surface is fixed, the transfer material is reversely conveyed by the switchback reverse conveyance mechanism E and passes again through the registration roller pair 35. By bringing the separation claw 44a into contact with the pressure roller 41 at the timing detected by the transfer material sensor 51, the time for contacting the separation claw 44a with the pressure roller 41 can be shortened, and the pressure roller sliding by the separation claw 44a can be shortened. It is possible to further reduce the occurrence of image defects due to scratches.
２）画像形成装置の作像部は、実施例では転写方式の電子写真作像機構であるが、これに限られず任意である。例えば、転写紙として感光紙を用いた直接方式の電子写真作像機構、転写方式あるいは直接方式の静電記録プロセス機構や磁気記録作像機構であってもよい。 2) The image forming unit of the image forming apparatus is a transfer type electrophotographic image forming mechanism in the embodiment, but is not limited thereto and is arbitrary. For example, a direct type electrophotographic image forming mechanism using a photosensitive paper as a transfer paper, a transfer type or direct type electrostatic recording process mechanism, or a magnetic recording image forming mechanism may be used.
３）定着装置は、実施例では定着ローラと加圧ローラを用いたヒートローラ型の定着装置であるが、これに限られず任意である。例えば、加圧ローラも熱源としてのヒータを内部に有する定着ローラとすることもできる。定着ローラの加熱方式も電磁誘導加熱機構にするなど任意である。圧力定着装置であってもよい。定着ローラ・加圧ローラは回転体に限られず、無端ベルトタイプの回転体の形態のものにすることもできる。 3) In the embodiment, the fixing device is a heat roller type fixing device using a fixing roller and a pressure roller, but is not limited thereto and is arbitrary. For example, the pressure roller may be a fixing roller having a heater as a heat source therein. The heating method of the fixing roller is arbitrary, such as an electromagnetic induction heating mechanism. It may be a pressure fixing device. The fixing roller and the pressure roller are not limited to a rotating body, and may be in the form of an endless belt type rotating body.
１２：操作パネル、１２ａ：余白幅入力部、４０：定着ローラ、４１：加圧ローラ、
４３：定着分離機構、４４：加圧分離機構、４３ａ・４４ａ：分離爪、
４３ｅ・４４ｅ：ソレノイド、
Ｄ：作像部、Ｎ：ニップ部、Ｅ：定着装置、Ｆ：スイッチバック反転搬送機構。
12: operation panel, 12a: margin width input unit, 40: fixing roller, 41: pressure roller,
43: fixing separation mechanism, 44: pressure separation mechanism, 43a and 44a: separation claw,
43e, 44e: Solenoid,
D: Image forming section, N: Nip section, E: Fixing device, F: Switchback reverse conveyance mechanism.
Claims (7)
前記第１の回転体に接離動作する第１の記録材分離部材と、
前記第２の回転体に接離動作する第２の記録材分離部材と、
前記第１の記録材分離部材を前記第１の回転体に対して接離動作させる第１の動作手段と、
前記第２の記録材分離部材を前記第２の回転体に対して接離動作させる第２の動作手段と、
前記作像手段において記録材上に画像形成する際に記録材搬送方向先端余白幅及び記録材搬送方向後端余白幅を可変設定できる余白幅可変設定手段と、
前記余白幅可変設定手段で設定した記録材搬送方向先端余白幅または記録材搬送方向後端余白幅に応じて、前記片面画像形成モードの定着実行時と前記両面画像形成モードの定着実行時においては前記第１の動作手段と前記第２の動作手段についてそれぞれ記録材分離部材を回転体に対して当接または離間の動作制御する制御手段と、
を有することを特徴とする画像形成装置。 An image forming means for forming an unfixed toner image on a recording material, and an unfixed toner image carrying of the recording material for forming a nip portion and sandwiching and conveying the recording material at the nip portion to heat and fix the unfixed toner image A single-sided image forming mode for forming an image on one surface of a recording material, and a fixing unit including a first rotating body facing the surface side and a second rotating body facing the opposite surface side; In an image forming apparatus capable of selecting a double-sided image forming mode in which an unfixed toner image is formed on two surfaces of a recording material on which one-sided image has been formed that has passed through the fixing unit and heated and fixed by the fixing unit.
A first recording material separating member that contacts and separates from the first rotating body;
A second recording material separating member that moves toward and away from the second rotating body;
First operating means for moving the first recording material separating member into and out of contact with the first rotating body;
Second operating means for moving the second recording material separating member into and out of contact with the second rotating body;
Margin width variable setting means capable of variably setting the leading edge margin width in the recording material conveyance direction and the trailing edge margin width in the recording material conveyance direction when forming an image on the recording material in the image forming means;
Depending on the leading-edge margin width in the recording material conveyance direction or the trailing-edge margin width in the recording material conveyance direction set by the margin width variable setting means, when fixing in the single-sided image formation mode and fixing in the double-sided image formation mode, Control means for controlling the contact or separation of the recording material separating member with respect to the rotating body with respect to the first operating means and the second operating means;
An image forming apparatus comprising:
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010145619A (en) * | 2008-12-17 | 2010-07-01 | Kyocera Mita Corp | Fixing apparatus and image forming apparatus |
| JP2010191273A (en) * | 2009-02-19 | 2010-09-02 | Sharp Corp | Image forming apparatus |
| JP2011164260A (en) * | 2010-02-08 | 2011-08-25 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus |
| JP2014081607A (en) * | 2012-09-27 | 2014-05-08 | Ricoh Co Ltd | Image forming apparatus |
| US8737859B2 (en) | 2011-11-30 | 2014-05-27 | Ricoh Company, Ltd. | Image forming apparatus capable of reducing jam in fixing unit |
| JP2014142559A (en) * | 2013-01-25 | 2014-08-07 | Ricoh Co Ltd | Fixing apparatus and image forming apparatus |
-
2003
- 2003-12-15 JP JP2003416769A patent/JP2005173486A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010145619A (en) * | 2008-12-17 | 2010-07-01 | Kyocera Mita Corp | Fixing apparatus and image forming apparatus |
| JP2010191273A (en) * | 2009-02-19 | 2010-09-02 | Sharp Corp | Image forming apparatus |
| JP2011164260A (en) * | 2010-02-08 | 2011-08-25 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus |
| US8737859B2 (en) | 2011-11-30 | 2014-05-27 | Ricoh Company, Ltd. | Image forming apparatus capable of reducing jam in fixing unit |
| JP2014081607A (en) * | 2012-09-27 | 2014-05-08 | Ricoh Co Ltd | Image forming apparatus |
| JP2014142559A (en) * | 2013-01-25 | 2014-08-07 | Ricoh Co Ltd | Fixing apparatus and image forming apparatus |
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